Various methods were tried in an attempt to obtain a technique for quantifying the gnawing effects of apomorphine on rats. A technique using a restraining tube was developed. Under a 2 milligram per kilogram intraperitoneal injection of apomorphine, four female Long Evans hooded rats were placed on continuous and fixed reinforcement schedules using a gnawable pine block. Subjects would learn to turn their heads away from the gnawable object in order to obtain 15 seconds of gnawing time. The rate of response increased from less than one response in 5 minutes to over 3 responses per minute in 10 one-half hour conditioning sessions. Rates of response stabilized during the last 5 experimental sessions and fixed ratio schedules of up to 5:1 were obtained in five additional 1 '1/ 2 hour sessions.